Effect of post-processing time on the physical and chemical characteristics of Nile tilapia fillets

Abstract

Brazil stands out as the fourth largest country on the global scale in terms of tilapia production. Authough the species presents a well-developed technological package compared to other species, studies on the fillet quality still need to be further addressed and face challenges. This study aimed to evaluate physical, chemical, and sensory parameters in fillets of 60 specimens of Nile tilapia (Oreochromis niloticus), divided into 4 treatments: obtaining the fillets, one day before the expiration date predicted by the slaughterhouse, two days after expiration, and four days after expiration. The pH increased significantly with post-processing time; the fillets evaluated close to and after the expiration date had higher shear force values, resulting in a more rigid meat. The cooking loss showed higher values in the fillets evaluated after the expiration date, indicating that the fillets lost a large part of their weight after their cooking. The water retention capacity showed that the fillets analyzed on the day of arrival presented less loss, which indicates a higher water retention. A difference was detected for the refrigeration loss (p<0.05), indicating that the longer the shelf life, the greater the water loss, showing a large difference between the fillets that were evaluated on the day of their arrival (2.02%) and the last fillets evaluated four days after their expiration date (16.67%). After the end of the expiration date, the protein concentration decreased considerably the same pattern found for total lipids.